In this paper, we present an ab-initio study on energy configurations, minimum energy path (MEP), and migra-tion energy for neutral indium diffusion in a uniaxial and biaxial tensile strained {100} silicon layer for the first time to our knowledge. Our ab-initio calculation of the elec-tronic structure allowed us to figure out transient atomistic configurations during the indium diffusion in strained sili-con. We employed the nudged elastic band (NEB) method for estimating the MEP between the two structural states. The NEB method teaches us that the diffusion pathway of neutral indium is kept unchanged in strained silicon while the migration energy of indium fluctuates in strained sili-con.